Interferometers with coated polarizing beam splitters that are rotated to optimize extinction ratios
AssigneeAgilent Technologies, Inc.
InventorElizabeth A. Nevis
Life of this patent
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Abstract
An interferometer includes a two-frequency laser and a polarizing beam splitter (PBS) that separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.
Claims12
An interferometer comprising:
- a laser system that produces a heterodyne beam including a first frequency component having a first polarization and a second frequency component having a second polarization;
- a coated polarizing beam splitter oriented so that the heterodyne beam has a non-zero incidence angle with the coated polarizing beam splitter, the coated polarizing beam splitter splitting the heterodyne beam into a first beam and a second beam respectively having the first and second frequencies;
- and
- interferometer optics that generate measurement and reference beams from the first and second beams.
An interferometer comprising:
- a laser system that produces a heterodyne beam including a first frequency component having a first polarization and a second frequency component having a second polarization;
- a polarizing beam splitter containing a coating oriented so that the heterodyne beam has an incidence angle with the coating that differs from 45°, the coating splitting the heterodyne beam into a first beam and a second beam respectively having the first and second frequencies;
- and
- interferometer optics that generate measurement and reference beams from the first and second beams.
Dependencies are inferred from the claim text.